Field of the Invention
The present invention relates to a scanning method and apparatus of an STA, and more specifically, to a method and apparatus of an STA performing active scanning.
Related Art
Wireless LAN techniques are nowadays evolving largely in three directions. In line with the existing wireless LAN evolution, an effort to further accelerate transmission rate includes IEEE (Institute of Electrical and Electronic Engineers) 802.11ac and IEEE 802.11ad. IEEE 802.11ad is a wireless LAN technique that adopts a 60 GHz band. Further, a broadband wireless LAN technique is highlighted to allow for a wider area of transmission as compared with the existing WLAN technology, and this technique employs a frequency band of 1 GHz or less, which includes IEEE 802.11af using the TVWS (TV white space) band and IEEE 802.11ah using a 900 MHz band. These technologies are primarily oriented towards expansion of extended range Wi-Fi services as well as smart grid and wide area sensor networks. Moreover, the conventional WLNA MAC (medium access control) techniques sometimes suffer from a delayed initial link setup time. In order to address such issue to enable quick access of an STA to an AP, brisk activities to standardize IEEE 802.11ai are recently underway.
IEEE 802.11ai is an MAC technology to treat a quick authentication procedure for remarkably saving the initial setup and association time of WLAN, and its standardization dates back to January, 2011 with a regular task group. In order for a quick access procedure, IEEE 802.11ai is in discussion for simplification of processes in light of AP discovery, network discovery, TSF sync (time synchronization function synchronization), authentication & association, and merge with higher layers in process. Among others, process merge utilizing piggyback of DHCP (dynamic host configuration protocol), optimization of full EAP (extensible authentication protocol) using concurrent IP, and efficient selective AP (access point) scanning or other ideas are in vigorous discussion.